4Dasgupta S,Dasgupta S,Sharma PP,et al.Ultrasound assessment of endometrial cavity in perimenopausal women on oral progesterone for abnormal uterine bleeding:comparison of diagnostic accuracy of imaging with hysteroscopy-guided biopsy[J].J Obstet Gynaecol Res,2011,37(11):1575-1581.
5Geller SE, Adams MG.Kelly PJ,et aL Postpartum hemorrhagein resourcepoorsettingsCJD. Int J Gynaecol Obstet, 2006, 92:202-211.
6Nour NM. An introduction to maternal mortality CJD.Rev Ob-stet Gynecoh 2008. 1(2) :771-773.
7MacDortnan MF, Menacker F, Declercq E. Cesarean birth inthe United States: epidemiology, trends, and outcomes〔J〕.Clin Perinatol, 2008,35 : 293-307.
